Ortho acid

Ortho acids are a class of acids characterized by having the maximum number of hydroxyl groups that can be attached to a central atom, given its valence. They are more commonly referred to in the context of their derivatives, especially when discussing inorganic chemistry. Ortho acids are contrasted with their less hydrated forms, known as meta acids or pyro acids, depending on the degree of dehydration.

Structure and Nomenclature

The general formula for an ortho acid is represented as H_n+2EOn, where E represents the central atom, usually a nonmetal or a metalloid, and n is the number of oxygen atoms bonded to E. The n+2 indicates the number of hydrogen atoms, which are typically bonded to the oxygen atoms in the form of hydroxyl groups. This structure allows ortho acids to exhibit strong acidic properties, as the hydroxyl groups can easily donate protons (H^+ ions) in aqueous solutions.

Ortho acids are named by adding the prefix ortho- to the name of their corresponding anhydride or less hydrated form. For example, orthophosphoric acid (H_3PO_4) is derived from phosphoric acid, which itself can exist in less hydrated forms such as pyrophosphoric acid (H_4P_2O_7) and metaphosphoric acid (HPO_3).

Examples

Some common examples of ortho acids include:

• Orthophosphoric acid (H_3PO_4) - Commonly known as phosphoric acid, it is widely used in the manufacture of fertilizers and soft drinks.
• Orthosilicic acid (H_4SiO_4) - Found in natural waters, it plays a crucial role in the biogeochemical cycle of silicon.
• Orthoboric acid (H_3BO_3) - Also known as boric acid, it is used in various applications ranging from industrial manufacturing to antiseptic products.

Properties

Ortho acids typically have higher melting points and boiling points compared to their less hydrated counterparts due to the presence of hydrogen bonds between the hydroxyl groups. They are also generally more soluble in water and exhibit stronger acidity. The strength of an ortho acid can be influenced by the electronegativity of the central atom and the stability of the resulting anion after deprotonation.

Applications

Ortho acids find applications across a broad spectrum of fields. In industry, they are used in the synthesis of plastics, detergents, and various chemicals. In agriculture, they serve as key ingredients in fertilizers to provide essential nutrients to plants. In the medical field, certain ortho acids have antiseptic properties and are used in pharmaceutical formulations.

See Also

• Acid
• Inorganic chemistry
• Hydroxyl group
• Proton
• Fertilizer
• Antiseptic